Snow-clearing vehicle

ABSTRACT

A snow-clearing vehicle comprises a carrier vehicle and, attached to the front end thereof via a carrying device, a snowplow with at least one plowshare segment mounted to be variable in position in such a way that, upon encountering an obstruction, it executes an evasive movement to take it out of an operating position. In the process, at least one restoring spring exerts resistance in opposition to the evasive movement and returns the plowshare segment to the operating position after the obstruction has been passed. Furthermore, a braking device with electrically adjustable brake characteristic acting parallel to the restoring spring at least over part of the evasive movement and a transducer acting on the braking device via an electrical interface are provided.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to German Patent Application No. 102016121205.9, filed Nov. 7, 2016, the contents of which are incorporated herein by reference.

The present invention relates to a snow-clearing vehicle. In particular, the present invention relates to such a snow-clearing vehicle that comprises a carrier vehicle and, attached to the front end thereof via a carrying device, a snowplow with at least one plowshare segment mounted to be variable in position in such a way that, upon encountering an obstruction, it executes an evasive movement to take it out of an operating position, wherein at least one restoring spring exerts resistance in opposition to the evasive movement and returns the plowshare segment to the operating position after the obstruction has been passed.

To prevent damage to the snowplow and/or an obstruction that this encounters during clearing operation (e.g. raised manhole cover or roadway transition), it is known to mount the plowshare or several individual plowshare segments in such a way that, upon encountering an obstruction, it/they executes/execute an evasive movement to take it/them out of an operating position. Mounts suitable for this purpose may be constructed in different ways, especially by making them comprise several connecting rods (e.g. in parallel or trapeze configuration) or else curved guides. Typically, at least one restoring spring then acts on the one plowshare or the at least one plowshare segment in such a way that it exerts resistance in opposition to the evasive movement and returns the plowshare or the plowshare segment to the operating position after the obstruction has been passed. An example of the prior art can be found in DE 1708665 A.

In the past, it has occasionally been proposed that, besides the restoring spring, a retaining device be provided, on the basis of which that force needed to move the plowshare or the plowshare segment—at the beginning of the evasive movement—out of the operating position (“release force”) is noticeably larger than the restoring force acting during the ensuing further evasive movement. Thus because of the comparatively high release force of a so-called “hard” plow—a good clearing result is supposedly achieved even in the case of heavy and/or packed snow/ice, without any hindrance of the desired evasive movement of the plowshare upon encountering an obstruction due to the high resistance, which acts during the entire evasive movement. Such snowplows with a releasable retaining device, by which the plowshare is held in operating position with a retaining force greater than the restoring force of the restoring spring, are known, for example from U.S. Pat. No. 5,109,618 A, DE 4224220 A1, DE 3926801 A1 and DE 1963108 A1.

The object of the present invention was to provide a snow-clearing vehicle of the type mentioned in the introduction, improved with respect to the operating characteristics.

This object is achieved according to the present invention by providing, in the snow-clearing vehicle of the type mentioned in the introduction, a braking device with electrically adjustable brake characteristic acting parallel to the restoring spring at least over part of the evasive movement and a transducer acting on the braking device via an electrical interface. In the inventive snow-clearing vehicle, therefore, the evasion or operating characteristic of the snowplow is variable in real time during the ongoing snow-clearing operation, so that in particular—via exertion of influence on the braking device with electrically adjustable brake characteristic by the transducer—the reaction beginning when the plowshare or the plowshare segment encounters an obstacle can be actively changed in real time. It is therefore possible to react without delay to circumstances that change during the ongoing snow-clearing operation in such a way that the evasion characteristic is adapted or matched to the instantaneous circumstances (e.g. snow depth, snow consistency, ground, etc.) or is changed in other ways.

Particularly preferably, this transducer comprises an electronic control unit, which in turn is in communication with at least one sensor and which processes measured values already provided thereby. With this improvement, the evasion and operating characteristic of the snowplow can be continuously adapted completely automatically to the current circumstances that exist during ongoing snow-clearing operation by processing of typical characteristic data (e.g. mean clearing force, air temperature, vibration profile), wherein a measured value at least of one characteristic data sensor (e.g. force sensor, temperature sensor, vibration sensor, etc.) in the electronic control unit is used for the current adjustment of the brake characteristic of the braking device. In this way, for example, the braking device can be varied as a function of the clearing force—which is higher in the case of abundant and/or wet or packed snow than in the case of little and/or dry or loose snow acting during clearing operation and averaged over a specified time interval, in order to suppress premature evasive movement of the plowshare during clearing of very heavy snow. Alternatively, it is possible to deduce, for example from a vibration profile recorded during clearing operation, the condition of the traffic surface on which snow is to be cleared and to adapt the “hardness” of the snowplow automatically to the respective situation by changing the operating characteristic of the braking device; in the case of relatively smooth traffic surfaces and accordingly subdued vibration profile, the hardness of the snowplow can be automatically increased in the interests of an optimum clearing result. This is also possible by analogy for automatic allowance for other measured values characteristic of the clearing situation (see above) and used to vary the braking device and thus the evasive behavior.

Within the foregoing meaning, it is also possible in particular to construct such a snow-clearing vehicle in which a collision sensor is provided, the signal of which is delivered to an electronic control unit that changes the operating characteristic of the braking device. In this way—and this represents a quite particularly preferred improvement of the present invention—the characteristic of a collision of the at least one plowshare with an obstacle can be sensed and the brake force generated by the braking device can be changed as a function of the collision characteristic by means of a collision sensor (preferably disposed on the snowplow itself). In normal clearing operation, the snowplow can be operated in this way with a comparatively hard operating characteristic, i.e. a comparatively high release threshold for the evasive movement, thus permitting—without the risk of unwanted evasive movement of the plowshare—“hard” operation of the snowplow for “clearing to black” so to speak, even in the case of heavy and/or packed snow/ice. However, the release threshold is suddenly lowered by corresponding influence exerted via the control unit on the braking device when the collision sensor detects such a collision with an obstruction that forces an evasive movement of the at least one plowshare.

In this connection, the control unit explained in the foregoing and acting on the braking device may be self-learning with respect to at least one influencing variable in the respect that it comprises a learning module, which senses the “normal” typical characteristic data (e.g. the typical average impacts on the plowshare) that occur during the respective clearing operation and that depend on the specific operating circumstances (ground conditions, snow/ice conditions) and allows for them during adjustment of the braking device in the sense of strengthening or weakening the braking effect.

It is particularly advantageous when the braking device, depending on its design, delivers a braking effect that depends on the dynamic characteristic of the evasive movement, especially by increasing the generated braking force with the dynamic characteristic of the evasive movement of the plowshare segment in question. In the interests of exerting a highly dynamic influence of the control unit on the braking effect of the braking device, this device comprises, particularly preferably, a magnetorheological shock absorber. Besides the particularly short response time that is possible hereby for adjustment of the braking effect, the broad range of adjustment as well as the absence of moving parts is of great advantage. Such absence in turn favors good reproducibility of the brake characteristic of the braking device as well as high reliability (despite the extremely unfavorable environmental conditions such as humidity, frost, salt).

However, it is not only for the particularly preferred automatic exertion of influence, explained in the foregoing, on the braking device by means of an electronic control unit as a function of the signal/measured value of a collision or other sensor that it is particularly favorable that the braking device has an electrically operating adjustment mechanism, by means of which the brake characteristic of the braking device is variable, and an electrical interface in transmission communication with the adjusting mechanism. After all, this is in fact equally of advantage when an input unit, by means of which the operating characteristic of the braking device can be influenced manually, is disposed in the driver's cab of the snow-clearing vehicle. The possibility of changing the release response of the snowplow from the driver's cab during clearing operation permits the vehicle driver to take preemptive action, without interrupting the operation, to adapt the snowplow optimally to the respective momentary or immediately pending operating situation, for example when a snowfall has to be removed occasionally during a clearing operation intended primarily for removal of powder snow.

The electronically adjustable braking device is able to deliver a braking effect throughout the entire evasive movement of the plowshare, but does not have to do so. To the contrary, braking devices that generate a braking effect on only part of the evasive movement may also be used within the scope of the present invention. For example, the braking device or a component thereof having a braking effect, namely the magnetorheological shock absorber (see above) may be connected between the plowshare and a plow frame in such a way that, by virtue of the geometric conditions, it develops this opposing effect only during a first part of the evasive movement (close to the operating position). Furthermore, the braking device may be a veritable releasable retaining device, which is active exclusively in the operating position of the plowshare in such a way that a release force composed of the restoring force of the restoring spring and the retaining force is necessary in order to initiate the evasive movement.

Finally, in order to prevent misunderstandings, it must be pointed out that the entire plowshare is to be understood as a “plowshare segment” within the meaning of the present invention, if it is made without being subdivided and accordingly executes an evasive movement as a whole upon encountering an obstruction. Otherwise, several “plowshare segments” may be present not only in the case of a vertical subdivision of the plowshare into several portions disposed side-by-side, but also in the case of a horizontal subdivision of the plowshare (e.g. in so-called spring-flap plows). 

1. A snow-clearing vehicle, comprising: a carrier vehicle and, attached to the front end thereof via a carrying device, a snowplow with at least one plowshare segment mounted to be variable in position in such a way that, upon encountering an obstruction, it executes an evasive movement to take it out of an operating position, wherein at least one restoring spring exerts resistance in opposition to the evasive movement and returns the plowshare segment to the operating position after the obstruction has been passed, wherein a braking device with electrically adjustable brake characteristic acting parallel to the restoring spring at least over part of the evasive movement and a transducer acting on the braking device via an electrical interface are provided.
 2. The snow-clearing vehicle of claim 1, wherein the transducer comprises an electronic control unit, which in turn is in communication with at least one sensor and which processes measured values already provided thereby.
 3. The snow-clearing vehicle of claim 2, wherein a collision sensor is provided, the signal of which is delivered to the electronic control unit.
 4. The snow-clearing of claim 1, wherein the transducer comprises a manually operable input unit disposed in the driver's cab of the carrier vehicle.
 5. The snow-clearing vehicle of claim 1, wherein the braking device generates a braking force as a function of the dynamic characteristic of the evasive movement.
 6. The snow-clearing vehicle of claim 1, wherein the brake is equipped with a magnetorheological shock absorber.
 7. The snow-clearing vehicle of claim 1, wherein the braking device comprises a retaining device, the braking effect of which decreases suddenly during the evasive movement from a high release value. 